Transmission scheme over MAC for energy consumption reduction in wireless sensor networks based on IEEE 802.15.4

Recently, a lot of studies have been done in wireless sensor networks (WSNs) based on IEEE 802.15.4. While a sensor device transmits data to a PAN coordinator via a coordinator, the failure of radio communications may be occurred between a coordinator and a PAN coordinator. A coordinator may conclude that it has been orphaned and then perform the orphan scan procedure which is specified in IEEE 802.15.4. However, because a sensor device does not know the orphaned state of a coordinator, a sensor device transmits data to a coordinator continuously. In this case, the Tx energy of a sensor and Rx energy of a coordinator may be wasted unnecessarily. In this paper, we propose an efficient scheme by which a coordinator rapidly notifies a sensor device that a coordinator can´t receive data from a sensor device any longer. Therefore, we can reduce energy consumption required for transmission of a sensor device and reception of a coordinator.